Circuit breaker



May 20, 1947. G. J. EASLEY I CIRCUIT BREAKER Filed July '7, 1944 INVENTOR flberr fEaj/ey.

61, 2 WW7! ATTORNEY Patented May 20, 1947 CIRCUIT BREAKER Gilbert J. Easley, Forest Hills, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 7, 1944, Serial No. i3,9 12

11 Claims.

This invention relates to circuit breakers, and more particularly to circuit breaker operating mechanisms of the fluid pressure operated type.

When a circuit breaker of the fluid motor operated type is closed in against a fault existing on the circuit controlled by the breaker, it is desired to quickly reverse the direction of movement of the mechanism and to quickly operate the breaker to open position. The compressed gas admitted to the fluid motor for closing the breaker is, at this time, at full closing pressure thereby preventing opening movement of the mechanism. This pressure may be dumped by opening a dump valve or exhaust valve which permits collapse of the fluid pressure on the working side of the motor directly to atmosphere. Such dump valves usually fall into two main classes, (1) those that are operated entirely by electromagnetic means, and (2) those that are operated by fluid pressure. The electromagnetically operated clump valves require an electromagnet of such size as to preclude high speed opening of the valve. Fluid pressure operated dump valves require a second valve for admitting fluid pressure to open the dump valve. Control valves for controlling the opening of pneumatically operated dump valves are energized near the end of the closing stroke of the breaker when the contacts touch and a certain amount of time is required to build up sufiicient fluid pressure back of the dump valve to operate it.

It is therefore an object of the invention to provide a circuit breaker operating mechanism of the fluid motor operated type with an improved exhaust valve which is releasably restrained in closed position and when released is instantaneously moved to open position by fluid pressure previously provided.

Another object of the invention is to provide a circuit breaker operating mechanism of the fluid pressure operated type with an improved exhaust valve for quickly exhausting the working fluid pressure from the operating mechanism.

Another object of the invention is to provide a circuit breaker operating mechanism of the fluid pressure operated type with an improved high speed exhaust valve which is normally latched in closed position and which, When released, is operated at high speed to open position by the working fluid pressure of the operating mechanism.

Another object of the invention is to provide a circuit breaker operating mechanism of the fluid motor type with an improved exhaust valve which is releasably restrained in closed position by an electromagnetically operated latch, and which, when released, is operated to open position at high speed to quickly exhaust the working pressure from the fluid motor.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof Will be best understood from the following detailed description of one embodiment thereof when read in connection with the accompanying drawing in which:

Fig. 1 comprises an elevational view partly in section of a circuit breaker operating mechanism embodying the principles of the invention; and

Fig. 2 is a vertical sectional view taken on line II-II of Fig. 1.

Referring to the drawing, the operating mechanism includes a main casting I l which is formed to provide a cylinder l3 closed at the upper end by an integral part of the casting. The lower end of the cylinder I3 is closed by means of a member l5 secured thereto and having a relatively large port I! therein which is open to the atmosphere. An operating lever I9 is pivotally mounted at one end on the casting II and consists of a pair of spaced parallel levers pivotally connected at one end by means of a pivot pin 2| to the upper ends of a pair of parallel links 23 (only one being shown). The lower ends of the links 23 are pivoted by means of a pivot pin 25 on ears 2'! (only one being shown) projecting from the main casting H. The free ends of the operating levers l9 are rigidly connected by means of a cross membe 29 and carry a short shaft 31 the-rebetween, on which is mounted a latch roller 33 disposed between the levers [9.

The circuit breaker shown schematically at T9 is biased to open circuit position by means of an accelerating spring 11 and is connected to the operating mechanism by means of an operating rod 35. The breaker operating rod 35 is pivotally connected by a pivot pin 37 to the operating lever 19.

In order to holdthe breaker closed, the operating lever 19 is held in the closed position by means of a high speed latching mechanism including a main latch 39 pivotally supported on the main casting II by means of a pivot pin 41. The latch 39 is disposed between the levers I9 and is adapted to engage the roller 33 carried by the free ends of the breaker operating levers l9 to restrain the operating mechanism and the breaker in closed circuit position. The latch 39-is biased to latching position against a stop 43 by means of a spring pressed plunger 45 which engages a projection 41 of the latch. The plunger 45 is slidably mounted in an opening in a portion of the main casting H and is biased inwardly against the projection 41 of the latch 39 by means of a compression spring 149 surrounding the plunger 45 and disposed between a sleeve 5| threaded into the casting H,

and the head of the plunger. An adjustable nut 53 is provided on the outer end of the plunger 45 to limit the inward movement of the plunger.

The construction of the latch face of the main latch 39 is such that this latch, by itself, will not serve to hold the breaker operating lever I9 in latching position. An auxiliary latch 55 is provided for engaging and holding the main latch 39 in latching position. The auxiliary latch 55 is pivotally mounted on the casting II by means of a pivot pin 51 and has a latch projection 59 which engages under a tail portion SI of the main latch 39 in the latching position of the latching mechanism. The auxiliary latch 55 is biased to latching position by means of a compression spring 63 seated in a recess in the casting and engaging a projection of the latch 55. The auxiliary latch 55 is also provided with a projection 65 which extends directly over the upper end of a trip plunger 6! of an electromagnetic trip device 69. In addition to the trip plunger 61, the trip device comprises an E-shaped core 'II of magnetic material, an energizing coil I3 mounted on the center leg of th core II, and a movable armature I5. The trip plunger 9! is secured to the center portion of the armature I and extends upwardly through a guide opening in the center portion of the core II and through an opening in the horizontal portion of the main casting II.

When the trip device 69 is energized, the armature I5 is moved upwardly against the core II causing upward movement of the trip plunger 61. The upward movement of the trip plunger rotates the auxiliary latch 55 counterclockwise and disengages the projection SI of the main latch 39, whereupon the accelerating spring ll of the circuit breaker, shown schematically at I9, moves the breaker to the open circuit position, the operating lever I9 being rotated counterclockwise about its pivot 2| by the opening movement of the breaker. During the early part of the opening movement of the operating lever I9, the roller 33 forces the main latch 39 in a counterclockwise direction as it clears the latch. As soon as the roller 33 clears the main latch I9, the spring 49 acts to return the latch 39 to latching position.

Means is provided to prevent the restoration of the auxiliary latch 55 to its latching position until the operating lever I9 is returned to closed position. This means comprises a U-shaped holding lever 83, the legs of which are pivotally mounted on the pivot pin 51 on opposite sides of the auxiliary latch 55. The holding lever 83 is biased in a counterclockwise direction by a spring 85 compressed between a spring seat in the casting H and a projection 81 of the holding lever. The cross member 89 of the holding lever 83 is disposed directly beneath the free end of the operating lever I9 and thus is held in inoperative position when the operating lever is in closed position. When the operating lever is released and moves toward open position, the holding lever 83 is rotated counterclockwise at which time a lateral extension 9I of the holding lever 83 engages and holds the auxiliary latch 55 in unlatched position until the breaker operating arm I9 is returned to closed position and the roller 33 is reengaged by the latch face of the main latch 39. For this purpose, the biasing spring 85 of the holding lever 83 is of greater strength than the auxiliary latch biasing spring 63.

The breaker is adapted to be closed by conipressed gas admitted to the cylinder I3 above an operating piston 93. The piston 93 is secured to a piston rod slidable through an air-tight opening in the top wall of the cylinder II. A connector 91 is threadedly connected to the piston rod 95 and pivotally connected to the pivot pin 31 carried by the operating lever I9, thus directly connecting the piston 93 to the breaker operating rod 35.

Compressed air is admitted from an auxiliary air reservoir or tank (not shown) to the upper end of the cylinder I3 through an inlet passage controlled by a main inlet valve indicated generally at I03 secured to the side of the casting II. The opening operation of the main inlet valve I03 is, in turn, controlled by an electro magnetically operated pilot valve I95. The inlet valve I03 comprises a valve element I'II biased to closed position by means of a spring I13 and operable to open position by a piston I15 which is operated by compressed gas admitted thereto by operation of the pilot valve I05.

The pilot valve I05 is operated by an electromagnet I01 which, when energized, causes opening of the pilot valve I95 to admit compressed air from the tank (not shown) to the piston I15 to operate the main inlet valve III. Actuation of the inlet valve admits compressed air through an inlet port IT! to the upper end of the operating cylinder I3 which drives the piston quickly downwardly to close the breaker.

When the mechanism is operated to closed position, the operating lever I9 rotates in a clockwise direction, and near the end of this clockwise travel, the roller 33 engages the inclined surface of the main latch 39. As the roller passes along this inclined surface, the latch 39 is rotated counterclockwise until the roller passes the nose of the latch whereupon the retrieving spring 49 restores the main latch 39 to latching position. As the roller 33 passes the nose of the main latch 39, the cross member 29 on the free end of the operating lever I9 engages the free end of the holding lever 83 and rotates the holding lever clockwise to its normal position permitting the spring 83 to restore the auxiliary latch 55 clockwise to latching position.

An exhaust port H9 is provided for venting the cylinder I3 to atmosphere through the inlet passage when the breaker is tripped open from a fully closed position and there is no closing air in the cylinder. This port, however, is inadequate to dump the charge of closing air to permit quick reversal of the piston and opening of the breaker when the breaker is closed in against a fault.

When the circuit breaker is closed in against a fault and it is desired to quickly reverse the movement of the mechanism so that the circuit breaker may be quickly opened, it is necessary to quickly vent the closing fluid pressure from the working side of the piston 93. This is accomplished by opening an exhaust valve I09.

The exhaust valve I09 is mounted for sliding movement in a housing III which is secured to the side of the operating cylinder I3 by means of bolts I I3. The valve Ill-9 is disposed in the cylindrical lower portion II5 of the housing I I I and is biased to closed position by means of a spring 1. The exhaust valve is of the piston-type and comprises a valve member II9 integral with two piston valves I2I which cooperate with exhaust ports I23 formed in the upper and lower walls of the cylinder H5. The exhaust ports I23 in th upper wall of the cylinder H5 communicate with a chamber I25 in the upper portion of the housing I I I, and the chamber I25 communicates with the operating cylinder I3 by means of an exhaust port I21 in the wall of the cylinder. The ports I23 in the lower wallof the exhaust valve cylinder communicate directly to the atmosphere.

Disposed in the cylinder II5 to the right of the exhaust valve I09, but separable therefrom, is a pilot piston I3I having an integral stem stem I33 against which the exhaust valve IDS is biased by the spring I I1. A passage I35 in the housing III connects the chamber I25 to the working end of the cylinder H5. The left-hand end of the cylinder H5 is closed by member I31 suitably secured thereto. The spring H1 is compressed between the member I31 and the lefthand end of the exhaust valve. A rod I39 having one end threaded and screwed into the lefthand end of the valve member H9 is slidably supported in an opening MI in the member I31. The end of the rod I39 has a reduced portion I43 forming a shoulder I45 which is engaged by a latch rod I41 disposed for vertical sliding movement in an opening in the member I31. A U-shaped member I49 is adjustably secured to the upper end of the trip rod I41 by means of a pair of nuts I5I threaded onto the trip rod one above and one below the lower leg of the U-shaped member and tightened thereagainst. An electromagnet, indicated generally at I53, is provided for operating the latch I41 to release the dump valve. The electromagnet comprises an E-shaped core member I55 mounted on a bracket I51 secured to the housing II by means of one of the bolts H3, an energizing winding I59 surrounding the center leg of the core member and a movable armature I51. The armature I6'-I is mounted on the upper leg of the U-shaped member I49 by means of a headed bolt IE3 and a nut I65 disposed between the armature and the U-shaped member. The head of the bolt I53 is spaced below the upper leg of the U-shaped member to provide a lost motion connection between the armature IGI and the latch rod I41. The purpose of the lost motion connection is to provide for high-speed operation of the latch rod I41.

During a. closing movement of the operating piston 93 and before the contacts touch, the piston passes below the exhaust port whereupon compressed gas at full closing pressure is applied through the chamber I25 and passage I35 to the working side of the pilot piston I3I. Neither the piston I3I nor the dump valve I09 can operate at this time since they are re strained by engagement of the latch rod I41 with the shoulder I45 on the rod I39. As the operating piston 93 continues its closing stroke, and just before the breaker arrives full closed position, th contacts touch. If, at this time, there is a fault on the line the trip device 69 is energized and operates the latch mechanism to permit opening movement of the breaker mechanism. At the same time the electromagnet I53 is energized and attracts the armature IBI upwardly to disengage the latch I41 from the shoulder I45, whereupon the previously built up pressure back of th pilot piston I3I drives the pilot piston and the exhaust valve IE9 at high speed toward open position. As soon as the exhaust valves crack open the compressed gas rushing through the exhaust ports I23 and past the faces of the valves |2I assist in moving the dump valve to full open position momentarily separating the valve I09 from the end of the stem I33 of the pilot valve. When th gas pressure is decreased a certain amount, the spring I' I1 becomes effective to move the exhaust valve toward closed position, but since the compressed gas trapped back of the pilot piston I3I is vented relatively slowly, the piston I3I is held in a position to maintain the exhaust valve open until the trapped gas is vented to a point where the spring II1 moves the exhaust valve I09 and the pilot piston I3I to the position shown in the drawing. As soon as the exhaust valve reaches its closed position the latch rod I41 is moved downwardly by the force of gravity or by spring means (not shown) and reengages the latching shoulder I45 on the rod I39, the reduced portion I43 of the rod I39 acting as a limit stop for the downward movement of the trip rod.

From the foregoing description it will be apparent that there is provided a high speed exhaust valve mechanism for the fluid pressure operated mechanism wherein the exhaust valve is latched and full operating fluid pressure is applied to operate said valve before the valve is released thereby providing for substantially instantaneous opening of the valve upon release thereof.

Having described the invention. in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from some of the essential features of the invention, and that come within the scope of the appended claims.

I claim as my invention:

1. In a circuit breaker comprising relatively movable contacts, operating mechanism therefor comprising a fluid operated motor, means for admitting fluid under pressure to said motor to operate said contacts to closed position, trip means operable in response to abnormal circuit conditions to effect opening movement of said contacts, a valve operable to cause quick collapse of the fluid pressure on the working side of said motor, pneumatically operated means for moving said valv to open position, means releasably restraining said valve in closed postion, electroresponsive means operable when energized to operate said restraining means to release said valve, and means for applying fluid pressure to said pneumatic means before said electroresponsive means is energized.

2. In a circuit breaker comprising relatively movable contacts, operating mechanism therefor comprising a fluid motor operable to close said contacts, means for admitting fluid under pressure to operate said motor, trip means operable in response to abnormal circuit conditions to effect opening of said contacts, valve means operable to cause quick collapse of the fluid pressure on the working side of said motor, pneumatically operable means for operating said valve means to open position, latch means normally restraining said valve and said pneumatic means against operation, electroresponsive means operable when energized to operate said latch and release said valve, and means comprising a passage for admitting fluid pressure to said pneumatic means befose said valve is released, said pneumatic means maintaining said valve open until the fluid pressure in said motor has collapsed below a predetermined value.

3. An operating mechanism for a circuit breaker comprising a cylinder and a piston movable therein to close said breaker, means for admitting fluid pressure to said cylinder to operate said piston to close said breaker, means comprising a valve operable to an open position for causing quick collapse of pressure in the cylinder and thereby permit high speed reversal of movement of said piston, latch means releasably restraining said valve in closed position, pneumatically operated means for actuating said valve to open position, and means for operating said latch means to release said valve and permit said pneumatically operated means to actuate said valve to open position, fluid pressure being applied to pneumatically operated means before said valve is released.

4. An operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid under pressure to said motor for operating said breaker to closed position, means comprising a valve operable to an open position during a closing operation of said motor for causing quick collapse of the fluid pressure on the Working side of said motor, actuating means operable by fluid pressure to actuate said valve to open position, latch means normally restraining said valve in closed position, electroresponsive means operable when energized to actuate said latch and release said valve, and means for applying fluid pressure to said actuating means before said valve is released.

5. In an operating mechanism for a circuit breaker, means comprising a fluid motor operable to close the breaker, an inlet valve operable to admit fluid pressure to said motor to effect closing of said breaker, means operable to cause opening of the breaker, a valve for collapsing the fluid pressure in said motor, fluid pressure operated actuating means for actuating said valve, and latch means for restraining said valve in closed position until after fluid pressure has been applied to said actuating means.

6. In an operating mechanism for a circuit breaker, means comprising a fluid motor operable to close the breaker, an inlet valve operable to admit fluid pressure to said motor to effect closing of said breaker, means operable to cause opening of the breaker, a valve for collapsing the fluid pressure in said motor, fluid pressure operated actuating means for actuating said valve, and latch means for releasably restraining said valve in closed position, and means operable after fluid pressure has been applied to said actuating means for operating said latch means to permit said actuating means to open said valve.

7. In an operating mechanism for a circuit breaker, means comprising a fluid motor operable to close the breaker, an inlet valve operable to admit fluid pressure to said motor to effect closing of said breaker, means operable to cause opening of the breaker, a valve for collapsing the fluid pressure in said motor, fluid pressure operated actuating means for actuating said valve to open position, latch means for restraining said valve in closed position, and means operable after fluid pressure has been applied to said actuating means for operating said latch to release said valve, said actuating means being maintained by trapped fluid pressure in a position to hold the valve open until after the fluid pressure in said motor has collapsed below a predetermined value.

8. In an operating mechanism for a circuit breaker, a fluid motor operable to close said breaker, means operable to admit fluid pressure to said motor to efiect closing of said breaker, means operable to cause opening of said breaker, a valve movable to an open position to cause quick collapse of fluid pressure in said motor, means engaging a part movable with said valve for releasably restraining said valve in closed position, pneumatic means for actuating said valve to open position, means effective during a closing stroke of said motor to admit fluid pressure to said pneumatic means, and electroresponsive means operable after fluid pressure is admitted to said pneumatic means to actuate said restraining means and release said valve.

9. In an operating mechanism for a circuit breaker comprising a fluid motor operable to close the breaker, an inlet valve operable to admit fluid pressure to said motor to eifect closing of the breaker, means operable to cause op ning of the breaker, an exhaust valve operable independently of said inlet valve to quickly collapse the fluid pressure in said motor to permit high speed reverse movement of said motor, fluid pressure actuating means for initiating opening movement of said exhaust valve, and latch means for releasably restraining said exhaust valve in closed position and operable after fluid pressure has been applied to said actuating means to release said exhaust valve.

10. In an operating mechanism for a circuit breaker comprising a fluid motor operable to close the breaker, an inlet valve operabl to admit fluid pressure to said motor to effect closing of the breaker, means operable to cause opening of the breaker, an exhaust valve operable mechanically independently of said inlet valve to quickly collapse the fluid pressure in said motor to permit high speed reverse movement of said motor, fluid pressure actuating means for initiating opening movement of said exhaust valve, and latch means for releasably restraining said exhaust valve in closed position, said latch means being operable after fluid pressure has been applied to said actuating means to release said exhaust valve.

11. In an operating mechanism for a circuit breaker comprising a fluid motor operable to close the breaker, an inlet valve operable to admit fluid pressure to said motor to effect closing of the breaker, means operable to cause opening of the breaker, an exhaust valve operable independently of said inlet valve to quickly collapse the fluid pressure in said motor to permit high speed reverse movement of said motor, fluid pressure actuating means for initiating opening movement of said exhaust valve, said exhaust valve being moved to full open position independently of said actuating means, latch means for releasably restraining said exhaust valve and said actuating means in closed position, and means operable after fluid pressure has been applied to said actuating means to release said exhaust valve.

GILBERT J. EASLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,164,134 Stansell et al Dec. 14, 1915 2,349,650 Cumming et al May 23, 1944 393,596 Westinghouse Nov. 27, 1888 

